IPAC2016 - List of Authors (Kobayashi, Y.)

Paper	Title	Page
MOPOY025	Electromagnetic Design of β=0.13, f=325 Mhz Half-Wave Resonator for Future High Power, High Intensity Proton Driver at KEK	902
	G.-T. Park, E. Kako, Y. Kobayashi, T. Koseki, S. Michizono, F. Naito, H. Nakai, K. Umemori, S. Yamaguchi KEK, Ibaraki, Japan T. Maruta KEK/JAEA, Ibaraki-Ken, Japan
	At KEK, a proposal is being prepared for a new linac-based proton driver that can accelerate the proton beam up to 9 GeV with 9 MW beam power and 100 mA peak current. In this report, we present the study on the front end design of the linac, which will accelerate the beam to 1.2 GeV: The baseline layout, the acceleration energy structure, RF characteristics of components, cryomodule configurations, and the detailed design of half-wave resonator 1.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY025
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TUPOW036	Recent Developments and Operational Status of the Compact ERL at KEK	1835
	T. Obina, M. Adachi, S. Adachi, T. Akagi, M. Akemoto, D.A. Arakawa, S. Araki, S. Asaoka, M. Egi, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, X.J. Jin, E. Kako, Y. Kamiya, H. Katagiri, R. Kato, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondo, T. Konomi, A. Kosuge, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sakanaka, S. Sasaki, K. Satoh, Y. Seimiya, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, O. Tanaka, Y. Tanimoto, N. Terunuma, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, J. Urakawa, K. Watanabe, M. Yamamoto, N. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida KEK, Ibaraki, Japan R. Hajima, M. Mori, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma QST, Tokai, Japan M. Kuriki Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
	The Compact Energy Recovery Linac (cERL) at KEK is a test accelerator in order to develop key components to realize remarkable ERL performance as a future light source. After the beam commissioning in December 2013, the legal current limit has been increased step-by-step like 1 uA, 10 uA, and 100 uA. Survey for the source of beam losses has been conducted in each step, and the study on beam dynamics and tuning has also been carried out. As a next step, 1 mA operation is scheduled in February 2016. In parallel to the increase in beam current, a laser Compton scattering (LCS) system which can provide high-flux X-ray to a beamline has been successfully commissioned. We report recent progress in various kinds of beam tuning: improvement of electron gun performance, high bunch charge operation, mitigation of beam losses, LCS optics tuning and bunch compression for THz radiation.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW036
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WEPMB014	Cavity Performance of the Prototype KEK Superconducting RF Gun	2148
	T. Konomi, E. Kako, E. Kako, Y. Kobayashi, Y. Kobayashi, K. Umemori, K. Umemori, S. Yamaguchi KEK, Ibaraki, Japan R. Matsuda Mitsubishi Heavy Industries Ltd. (MHI), Takasago, Japan T. Yanagisawa MHI, Hiroshima, Japan
	A superconducting RF (SRF) gun can generate a high current and high energy beam. It has a possibility to achieve requirement from high performance ERL and high repetition FEL. Target values of the L-band KEK SRF gun are that beam repetition is 1.3 GHz, beam current is 100 mA, beam energy is 2 MeV, emittance is 1 mm mrad or less. The number of cell is 1.5. Accelerating energy of 2 MeV corresponds to 42 MV/m of maximum surface field. The photocathode is designed to be illuminated by excitation laser from backside. The SRF gun cavity consists of the 1.5 cell accelerating cavity, cathode plug and choke filter for protecting the heating of cathode plug. To evaluate these parts individually, these parts are added step by step. High gradient test of the accelerating cell without cathode plug and choke filter was done. The surface peak electric field reached 66 MV/m, and this meet the target value 42 MV/m sufficiently. Next high gradient test will be done after adding the choke filter. The choke filter is designed to be simple to wash choke cell easier. In this conference, we will report the design, fabrication and high gradient performance of the SRF gun cavity with choke filter.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB014
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WEPMB015	Construction and 2K Cooling Test of Horizontal Test Cryostat at KEK	2151
	K. Umemori, K. Hara, E. Kako, Y. Kobayashi, Y. Kondo, H. Nakai, H. Sakai, S. Yamaguchi KEK, Ibaraki, Japan
	A horizontal test cryostat was designed and constructed at AR East building on KEK. Main purposes of test stand are improvement of module assembly technique and effective development of module components. Diameter of vacuum chamber is 1 m and its length is 3 m, which is enough to realize performance test of L-band 9-cell cavity with full assembly, including input couplers, HOM dampers/couplers and frequency tuners. On the sides, several ports are prepared to access to components, such as coupler and tuners. A cold box is placed on the top of the chamber. Liquid He is filled in a 4K-pod and 2K He is supplied through a J-T valve. A He pumping system is prepared. Inside of the chamber was covered with 80K shield, which is cooled by Liquid nitrogen. A cavity is supported on 5K table, which is also used as 5K thermal anchors. After cooling down to 80K using liquid Nitrogen, 4K He was stored and pumped down to 2K. The cooling test was successful. In this presentation, details of design and construction of the horizontal test cryostat is described and results of the cooling tests are shown. High power tests will be realized in near future.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB015
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WEPOW020	Present Status of KEK Photon Factory and Future Project	2871
	T. Honda, M. Adachi, S. Asaoka, K. Haga, K. Harada, Y. Honda, X.J. Jin, T. Kageyama, R. Kato, Y. Kobayashi, K. Marutsuka, T. Miyajima, H. Miyauchi, S. Nagahashi, N. Nakamura, K.N. Nigorikawa, T. Nogami, T. Obina, M. Ono, T. Ozaki, H. Sagehashi, H. Sakai, S. Sakanaka, H. Sasaki, Y. Sato, M. Shimada, T. Shioya, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, O. Tanaka, Y. Tanimoto, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, K. Watanabe, M. Yamamoto, N. Yamamoto, Ma. Yoshida, S.I. Yoshimoto KEK, Ibaraki, Japan
	Two synchrotron radiation sources of KEK, the PF-ring and the PF-AR, continue their user operation with various improvements. Scrap and build of the first generation undulators of 1980s at the PF-ring is pushed forward year by year. Five new elliptically polarized undulators have been installed in these five years, and we have also installed four very narrow-gap short-period undulators generating high brilliant X-ray. The new beam transport line that enables the 6.5-GeV full energy injection for PF-AR will be completed by the end of 2016 in order to make the top-up operation of the two SR sources compatible with the continuous injection for two main rings of the Super-KEKB. We have proposed a project of further upgrade of the 2.5-GeV PF-ring to improve its horizontal emittance as 8 nm rad using combined bending magnets at the arc sections. And we are also moving ahead on proposal of constructing a new KEK light source of an extremely low emittance as 0.3 nm rad. The progress and detail of our future project will be described in this paper.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW020
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WEPOW021	The Low Emittance Reconstruction of the Arc Section of the Photon Factory	2874
	K. Harada, Y. Kobayashi, N. Nakamura, K. Oide, H. Sakai, S. Sakanaka KEK, Ibaraki, Japan
	The present horizontal emittance of the Photon Factory (PF) ring is about 35.4 nmrad. By the reconstruction of the normal cells at the arc section, the emittance can be reduced to about 8 nmrad. The double number of the combined function short bending magnets are adopted and one present normal cell become two new normal cells. Although the lattice of the straight sections are not changed, the optics are optimized to reduce the non-linear effects of the sextupoles of the arc sections. By keeping the tune advance of the straight section as 3 for the horizontal direction and 2.5 for the vertical, the dynamic aperture as large as that of the present ring can be achieved with the magnetic errors. The difference of the optics of the straight sections are so little that the beam injection and the operation of the in-vacuum short-gap undulators can be maintained. The hardware design will be began as the next step for the realization of the plan. In this proceedings, the design, optimization and simulation results for the low emittance lattice are shown.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW021
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THPMB012	The HMBA Lattice Optimization for the New 3 GeV Light Source	3251
	K. Harada, M. Adachi, N. Funamori, T. Honda, Y. Kobayashi, N. Nakamura, K. Oide, H. Sakai, S. Sakanaka, K. Tsuchiya KEK, Ibaraki, Japan
	For the design study of the HMBA (hybrid multi bend achromat) type most advanced light source, the new storage ring was designed from the lattice of the phase II upgrade project of the ESRF (ESRF II). Although the original 3 GeV test lattice from Dr. Pantaleo Raimondi of ESRF has no problem about the optical and magnetic parameters including the dynamic aperture, we reduce the cell numbers and inserted the short straight sections for the in-vacuum short-gap undulators. After the optimization of the linear and non-linear optics as the original design principle of ESRF II, the altered lattice has the circumference of about 440 m with 16 HMBA cells, the emittance about 440 pm rad with the intra-beam scattering effect at the beam current of 500 mA, and the large dynamic aperture of about 2 cm at the injection point even with the usual magnetic errors.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB012
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Paper

Title

Page

Electromagnetic Design of β=0.13, f=325 Mhz Half-Wave Resonator for Future High Power, High Intensity Proton Driver at KEK

902

G.-T. Park, E. Kako, Y. Kobayashi, T. Koseki, S. Michizono, F. Naito, H. Nakai, K. Umemori, S. Yamaguchi
KEK, Ibaraki, Japan
T. Maruta
KEK/JAEA, Ibaraki-Ken, Japan

At KEK, a proposal is being prepared for a new linac-based proton driver that can accelerate the proton beam up to 9 GeV with 9 MW beam power and 100 mA peak current. In this report, we present the study on the front end design of the linac, which will accelerate the beam to 1.2 GeV: The baseline layout, the acceleration energy structure, RF characteristics of components, cryomodule configurations, and the detailed design of half-wave resonator 1.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY025

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TUPOW036

Recent Developments and Operational Status of the Compact ERL at KEK

1835

T. Obina, M. Adachi, S. Adachi, T. Akagi, M. Akemoto, D.A. Arakawa, S. Araki, S. Asaoka, M. Egi, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, X.J. Jin, E. Kako, Y. Kamiya, H. Katagiri, R. Kato, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondo, T. Konomi, A. Kosuge, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sakanaka, S. Sasaki, K. Satoh, Y. Seimiya, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, O. Tanaka, Y. Tanimoto, N. Terunuma, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, J. Urakawa, K. Watanabe, M. Yamamoto, N. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida
KEK, Ibaraki, Japan
R. Hajima, M. Mori, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma
QST, Tokai, Japan
M. Kuriki
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan

The Compact Energy Recovery Linac (cERL) at KEK is a test accelerator in order to develop key components to realize remarkable ERL performance as a future light source. After the beam commissioning in December 2013, the legal current limit has been increased step-by-step like 1 uA, 10 uA, and 100 uA. Survey for the source of beam losses has been conducted in each step, and the study on beam dynamics and tuning has also been carried out. As a next step, 1 mA operation is scheduled in February 2016. In parallel to the increase in beam current, a laser Compton scattering (LCS) system which can provide high-flux X-ray to a beamline has been successfully commissioned. We report recent progress in various kinds of beam tuning: improvement of electron gun performance, high bunch charge operation, mitigation of beam losses, LCS optics tuning and bunch compression for THz radiation.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW036

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WEPMB014

Cavity Performance of the Prototype KEK Superconducting RF Gun

2148

T. Konomi, E. Kako, E. Kako, Y. Kobayashi, Y. Kobayashi, K. Umemori, K. Umemori, S. Yamaguchi
KEK, Ibaraki, Japan
R. Matsuda
Mitsubishi Heavy Industries Ltd. (MHI), Takasago, Japan
T. Yanagisawa
MHI, Hiroshima, Japan

A superconducting RF (SRF) gun can generate a high current and high energy beam. It has a possibility to achieve requirement from high performance ERL and high repetition FEL. Target values of the L-band KEK SRF gun are that beam repetition is 1.3 GHz, beam current is 100 mA, beam energy is 2 MeV, emittance is 1 mm mrad or less. The number of cell is 1.5. Accelerating energy of 2 MeV corresponds to 42 MV/m of maximum surface field. The photocathode is designed to be illuminated by excitation laser from backside. The SRF gun cavity consists of the 1.5 cell accelerating cavity, cathode plug and choke filter for protecting the heating of cathode plug. To evaluate these parts individually, these parts are added step by step. High gradient test of the accelerating cell without cathode plug and choke filter was done. The surface peak electric field reached 66 MV/m, and this meet the target value 42 MV/m sufficiently. Next high gradient test will be done after adding the choke filter. The choke filter is designed to be simple to wash choke cell easier. In this conference, we will report the design, fabrication and high gradient performance of the SRF gun cavity with choke filter.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB014

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WEPMB015

Construction and 2K Cooling Test of Horizontal Test Cryostat at KEK

2151

K. Umemori, K. Hara, E. Kako, Y. Kobayashi, Y. Kondo, H. Nakai, H. Sakai, S. Yamaguchi
KEK, Ibaraki, Japan

A horizontal test cryostat was designed and constructed at AR East building on KEK. Main purposes of test stand are improvement of module assembly technique and effective development of module components. Diameter of vacuum chamber is 1 m and its length is 3 m, which is enough to realize performance test of L-band 9-cell cavity with full assembly, including input couplers, HOM dampers/couplers and frequency tuners. On the sides, several ports are prepared to access to components, such as coupler and tuners. A cold box is placed on the top of the chamber. Liquid He is filled in a 4K-pod and 2K He is supplied through a J-T valve. A He pumping system is prepared. Inside of the chamber was covered with 80K shield, which is cooled by Liquid nitrogen. A cavity is supported on 5K table, which is also used as 5K thermal anchors. After cooling down to 80K using liquid Nitrogen, 4K He was stored and pumped down to 2K. The cooling test was successful. In this presentation, details of design and construction of the horizontal test cryostat is described and results of the cooling tests are shown. High power tests will be realized in near future.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMB015

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WEPOW020

Present Status of KEK Photon Factory and Future Project

2871

T. Honda, M. Adachi, S. Asaoka, K. Haga, K. Harada, Y. Honda, X.J. Jin, T. Kageyama, R. Kato, Y. Kobayashi, K. Marutsuka, T. Miyajima, H. Miyauchi, S. Nagahashi, N. Nakamura, K.N. Nigorikawa, T. Nogami, T. Obina, M. Ono, T. Ozaki, H. Sagehashi, H. Sakai, S. Sakanaka, H. Sasaki, Y. Sato, M. Shimada, T. Shioya, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, O. Tanaka, Y. Tanimoto, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, K. Watanabe, M. Yamamoto, N. Yamamoto, Ma. Yoshida, S.I. Yoshimoto
KEK, Ibaraki, Japan

Two synchrotron radiation sources of KEK, the PF-ring and the PF-AR, continue their user operation with various improvements. Scrap and build of the first generation undulators of 1980s at the PF-ring is pushed forward year by year. Five new elliptically polarized undulators have been installed in these five years, and we have also installed four very narrow-gap short-period undulators generating high brilliant X-ray. The new beam transport line that enables the 6.5-GeV full energy injection for PF-AR will be completed by the end of 2016 in order to make the top-up operation of the two SR sources compatible with the continuous injection for two main rings of the Super-KEKB. We have proposed a project of further upgrade of the 2.5-GeV PF-ring to improve its horizontal emittance as 8 nm rad using combined bending magnets at the arc sections. And we are also moving ahead on proposal of constructing a new KEK light source of an extremely low emittance as 0.3 nm rad. The progress and detail of our future project will be described in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW020

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WEPOW021

The Low Emittance Reconstruction of the Arc Section of the Photon Factory

2874

K. Harada, Y. Kobayashi, N. Nakamura, K. Oide, H. Sakai, S. Sakanaka
KEK, Ibaraki, Japan

The present horizontal emittance of the Photon Factory (PF) ring is about 35.4 nmrad. By the reconstruction of the normal cells at the arc section, the emittance can be reduced to about 8 nmrad. The double number of the combined function short bending magnets are adopted and one present normal cell become two new normal cells. Although the lattice of the straight sections are not changed, the optics are optimized to reduce the non-linear effects of the sextupoles of the arc sections. By keeping the tune advance of the straight section as 3 for the horizontal direction and 2.5 for the vertical, the dynamic aperture as large as that of the present ring can be achieved with the magnetic errors. The difference of the optics of the straight sections are so little that the beam injection and the operation of the in-vacuum short-gap undulators can be maintained. The hardware design will be began as the next step for the realization of the plan. In this proceedings, the design, optimization and simulation results for the low emittance lattice are shown.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW021

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THPMB012

The HMBA Lattice Optimization for the New 3 GeV Light Source

3251

K. Harada, M. Adachi, N. Funamori, T. Honda, Y. Kobayashi, N. Nakamura, K. Oide, H. Sakai, S. Sakanaka, K. Tsuchiya
KEK, Ibaraki, Japan

For the design study of the HMBA (hybrid multi bend achromat) type most advanced light source, the new storage ring was designed from the lattice of the phase II upgrade project of the ESRF (ESRF II). Although the original 3 GeV test lattice from Dr. Pantaleo Raimondi of ESRF has no problem about the optical and magnetic parameters including the dynamic aperture, we reduce the cell numbers and inserted the short straight sections for the in-vacuum short-gap undulators. After the optimization of the linear and non-linear optics as the original design principle of ESRF II, the altered lattice has the circumference of about 440 m with 16 HMBA cells, the emittance about 440 pm rad with the intra-beam scattering effect at the beam current of 500 mA, and the large dynamic aperture of about 2 cm at the injection point even with the usual magnetic errors.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB012

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